Under an entailment criterion, the ontological commitments of a theory cannot be determined prior to resolving the debate between nominalists and realists about universals.

To play its appointed role, a criterion of ontological commitment should be ontologically neutral: it lets the theory speak for itself, as it were, without imposing ontological assumptions from the outside. Quinean criteria, however, by focusing only on the values of the (individual) variables, have been accused of being ontologically biased against realism about properties or universals because they fail to attach ontological significance to the predicate.[22] Consider ‘∃x Swims(x)’. According